Boymum, it's time to stop pretending that this split is amicable for the sake of our two children.
When you told your lawyer about the hidden camera - this insane invasion of privacy & frightening indication of a dysfunctional personality - why did your lawyer not tell you to report it to the police immediately?
I'm actually scared of his reaction, I decided to get a warning letter sent because he didn't seem to be taking what he'd done seriously
Of course you are.
He will laugh at your warning letter, & - apart from using it against you in some mad way - ignore its implications.
He will not "own" his actions of take you, your lawyer, or the consequences TO HIM of his behaviour seriously until you start throwing the full force of the law at him.
Stuff "amiable".
How "amiable" is it to spy on another human being?
Stuff "for the kids". I wouldn't want him anywhere near them. There is no going back from this OP, no playing happy families. I know it's complicated, & awkward, & scary.
But while you keep sending him the message that he is above the law & his treatment of you is without consequences, he is never going to stop tormenting you.
Or did they, but you hoped that a warning letter from a solicitor was the better option?
I can understand your fear. If ex is going to kick off about a warning letter from a solicitor about an illegal act which you both know he committed, then of course he's going to be even worse when you tell the police.
Can you not see that THIS IS EXACTLY WHY YOU NEED TO?
If your solicitor genuinely did not recommend you get straight on to the police, you need to sack them, & find one who knows what s/he is dealing with here.
If they did, but you ignored their advice - (& I do understand the fear, & the awful feeling that if we just keep things as mellow as possible, our abuser may be pacified) - you need to pay attention to PPs upthread telling you that this needs reporting, & for you to have some form of hotline, for instant recognition of your phone number, by your local cop shop.